The time that many Mac users have feared has arrived.
Malware for the mac is here and the question is , should you be concerned ? ,
Probably not , its around , but not on a great many computers.
It is called MacDefender , MacGuard , MacProtector & MacSecurity.
it will appear on your computer screen asking you to download one of them.
Don’t do it.
If you are not sure on things that appear on your computer screen , Mac or Windows , just do a Google search and that will tell you whether it is malicious software.
If you use Safari disable the “automatic opening of downloaded files”
Open Safari , go to preferences , and remove the tick
Once it is unchecked you should not have to be concerned about installing and opening malware for the mac
Finally if you have downloaded and installed MacGuard etc then read this support article from Apple on how to remove the malware.